Built by campaign operators, for campaign operators.

Signalstack started as an internal tool. We were running multichannel campaigns across three vendors and could not answer a simple question: had we already talked to this person, and on what channel?

The spreadsheet gymnastics were expensive, error-prone, and slow. Every drop list needed a human to reconcile. Every opt-out took a week to propagate. We were spending real money contacting people who had already said "no thanks" — or worse, already said "yes."

So we built the data layer we wished we had: deterministic identity resolution, a unified timeline, a suppression engine that respects each channel's rules. Then we packaged it up so other operators could stop paying the same tax.